Technical Field
The subject matter of this disclosure relates generally to regulating electric power.
Background of the Related Art
The modern electric utility industry began in the 1880s. It evolved from gas and electric carbon-arc commercial and street lighting systems. The first electricity generating station introduced the industry by featuring the four key elements of a modern electric utility system: reliable central generation, efficient distribution, a successful end-use (the light bulb), and a competitive price. When the main and only end-use of electric power was nighttime light bulbs, reliable central generation meant that electric power supply service was available all of the time for all of the electric power demand. In the late 1880s, power demand for electric motors brought the industry from mainly nighttime lighting to 24-hour service and dramatically raised electricity demand for transportation and industry needs. In addition, the original direct current (DC) electric system was quickly replaced by low frequency (50-60 Hz) alternating current (AC) systems.
Due to the critical importance of electric power in the economic development of society, the core electric system engineering planning requirement for a reliable electric power supply was broadly defined under the assumption of power supply availability all of the time for all electric demand end-uses. Electric power systems have historically been dimensioned to handle its annual coincident peak demand. Tariffs are based on the situation when there is peak demand. All these assumptions led to the engineering of an electric power infrastructure where supply growth (generation capacity power in Watts) constantly outpaces demand growth (average demand power in Watts). Electric power generation capacity has grown faster than average demand capacity since the industry inception, while the ratio of average demand power by generation capacity power (capacity factor) has steadily been between 40-50%. Today, appliances have unrestricted access to electric power. Many sensor-automated appliances respond to environmental factors without human interaction. For instance, weather variation causes power draw synchronization on temperature-sensing appliances such as refrigerators and air conditioners. When multiple appliances draw power synchronously, a resonant coincident peak demand phenomenon occurs.
Electric utilities are accountable for delivering power to their end-user customers 100% of the time. Those same customers pay for immediate access to power to serve their needs, applying that power to drive a broad range of electric appliances that meet specific end user requirements. Peak demand occurs when the need for power, i.e. customer utilization of power to operate their electric appliances, exceeds the base load generating capacity of a local ISO/RSO network. This coincident peak event triggers the acquisition of additional/higher cost generating capacity by the utility provider to meet their reliability obligation, the costs of which often are passed directly on to their customers.
Electric utility customers may have either a single building/property with many operating appliances and/or a number of buildings/properties spread across one or more metropolitan geographies (an operating environment). Within either a given building/property or Metropolitan Service Area (MSA), a set of common internal and external environmental factors will be evident, as in a range of + or −2 degrees Fahrenheit outside air temperature within the MSA or a similar narrow range of temperatures room-to-room within a customer's building/property. In any given operating environment, electric appliances with a similar function, e.g., sensor-automated environmental cooling, will exhibit a high degree of synchronous “on/off” operational behaviors. Thus, for example, it has been found that these appliances (such as air conditioners and refrigerators) demanded power simultaneously a high percentage of the time to maintain end-user operational objectives such as a target room temperature. When the majority of appliances are “on” simultaneously, a coincident peak is generated, requiring additional electric power supply resources to meet the appliances' electric power demand. A coincident peak demand event, which typically occurs less than 5% of the time during a given billing cycle, nevertheless can account for over 20% of the total cost of power charged by an electric utility to its end user customers.
There is a need in the art to provide a system that regulates an electric appliance's access to its power supply to systematically control coincident peak demand. This disclosure addresses this need.